Device for cutting and welding plastic band for use in automatic strapping machine

ABSTRACT

A device for cutting and welding a plastic band for use in an automatic strapping machine, which comprises: a table provided with a cutting and welding mechanism thereunder; an upper band holding member which is supposed to hold the tip of the strapping band when said band is completely fed to cover the full length of the bottom of the table; a lower band holding member having a projection, which is disposed under the upper band holding member; and pectinate heat blades which are supposed to melt and penetrate the overlapped two portions of the band and thereafter weld them by the energy of a press member.

United States Patent [191 Sato [ Nov. 13, 1973 [75] Inventor: YoshimasaSato, Kanagawa, Japan [73] Assignee: Ikegai Tekko Kabushiki Kaisha,Tokyo, Japan [22] Filed: Nov. 15, 1971 [21] Appl. No.: 198,855

[30] Foreign Application Priority Data Dec. 26, 1970 Japan 45/140533Dec. 26, 1970 Japan 45/140532 [52] U.S. Cl. 100/33 PB, 156/499, 156/502[51] Int. Cl B65b 13/32 [58] Field of Search 100/25, 26, 33 PB;

[56] References Cited UNITED STATES PATENTS 3,470,814 10/l969 Tschappu..100/33 PB 3,200,028 8/1965 Chisholm 100/33 PB 3,269,300 8/1966 Billettet a1. 100/33 PB 3,368,323 2/1968 Wood 100/33 PB Primary Examiner-BillyJ, Wilhite Attorney-Woodhams et al.

[5 7] ABSTRACT A device for cutting and welding a plastic band for usein an automatic strapping machine, which comprises: a table providedwith a cutting and welding mechunism thereunder; an upper band holdingmember which is supposed to hold the tip of the strapping band when saidband is completely fed to cover the full length of the bottom of thetable; a lower band holding member having a projection, which isdisposed under the upper band holding member; and pectinate heat bladeswhich are supposed to melt and penetrate the overlapped two portions ofthe band and thereafter weld them by the energy of a press member.

7 Claims, 17 Drawing Figures PATENTEDunv 13 1975 3,771,436

' SHEET 1 BF 4 I PRIORART 2 PRIORART PRIOR ART PRIOR ART 4| FIG. 3 FIG.4

F 5 PRIOR ART PATENTED NM 1 3 I973 SHEET 2 U? 4 FIG. 7

PATENTED N0! 13 1975 SHEEY 3 UF 4 PAIENTEOuavmms 3771.436

SHEET u U. 4

FIG. I2

DEVICE FOR CUTTING AND WELDING PLASTIC BAND FOR USE IN AUTOMATICSTRAPPING MACHINE BACKGROUND OF THE INVENTION a. Field of the InventionThe present invention relates to a device for cutting and welding astrapping band made of a thermoplastic material such as polypropylene,which is applicable to an automatic strapping machine for use instrapping the package by employing said strapping band.

b. Description of the Prior Art As for the device for cutting andwelding the strapping band according to the conventional automaticstrapping machine, the sequence of working thereof is asdiagrammatically summarized in FIGS. 1 of the appended drawings:

As shown in FIG. 1, the package 41 is placed on the table 42, the band43 is wound round both the package 41 and the table 42, and the bandholding member 44 holds the band 43 by pressing it against the table 42.

Next, as shown in FIG. 2, the band holding member 45 holds the band 43by pressing it against the table 42.

Then, as shown in FIG. 3, the heat plate 46 is inserted into theinterstice X formed by the band 43.

Subsequently, as shown in FIG. 4, the press member 47 ascends, cuts theband 43 by the cutter 47a thereof together with the cutter 44a of theband holding member 44, and thereafter presses the band 43 and the heatplate 46 against the table 42, thereby melting the surface of the band43 contacting with the heat plate 46.

After that, as shown in FIG. 5, the heat plate 46 is removed and themelted portions of the surface of the band 43 are pressed to adhere toeach other, whereby the strapping work is completed.

Then, the table 42 is pulled out and the package 41 comes to be strappedby virtue of the elasticity of the band 43. i

The foregoing conventional device, however, is defective in that itcannot afford a tightly bound state of strapping when dealing with asmall-sized package, and this defect is ascribable to the fact that theband holding member 44, the press member 47 and the band holding member45 of the cutting and welding mechanism beneath the table 42 are placedin a row and the width of the table 42 cannot be made smaller than thetotal width of these members, so that there inevitably occur intersticeswhich bring about the looseness' of strapping when the table 42 ispulled out.

SUMMARY OF THE INVENTION One object of the present invention is toprovide a device which can eliminate the foregoing defect of theconventional devices and is capable of tightly strapping even asmall-sized package on account of the contracted width of the tableemployed therefor.

Another object of the present invention is to provide a device havingthe band holding members arranged vertically as against the conventionalway of transversely arranging them in a row beneath the table, whichrenders it possible to contract the width of the table by the width ofone of these holding members and to minimize the occurrence ofinterstices between the band and the exterior of a package even whensaid package is of small size, thereby bringing about tight strapping ofthe package.

Still another object of the present invention is to provide a devicewherein the heat blade to melt the band is installed on the top of theheat member disposed under the table and capable of vertical movementand is so designed as to be pressed into the band exactly at a rightangle to thereby render 'a stable and firm welding portion and, at thesame time, minimizethe risk of damaging the heat blade.

BRIEF DESCRIPTION OF THE DRAWINGS Among the appended drawings, FIGS. 1 5are diagrammatic front views of the principal parts of the cutting andwelding device for the conventional automatic strapping machine, whereinthe state of working of said device is illustrated in due order.

FIG. 6 is a diagrammatic front view of the principal part of the deviceaccording to the present invention.

FIG. 7 is an illustration of the working mechanism of the table employedin the same embodiment as shown in FIG. 6.

FIG. 8 is an illustration of the working mechanism of the upper bandholding member employed in the same embodiment as above.

FIG. 9 is an illustration of the working mechanism of lower band holdingmember employed in the same embodiment as above.

FIG. 10 is an illustration of the working mechanism of the press memberemployed in the same embodiment as above.

FIG. 11 is an illustration of the working mechanism of the heat memberemployed in the same embodiment as above.

FIG. 12 is a diagrammatic longitudinal section of the table in relationto the mechanism for holding thereof employed in the same embodiment asabove.

FIGS. 13 15 are diagrammatic front views of the same embodiment asabove, wherein the state of working of the device is illustrated in dueorder.

FIG. 16 is a diagrammatic perspective view to show the relative positionof the heat member and the press member.

FIG. 17 is a diagrammatic perspective view to show the state of the bandwelded.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 6, the package 1 is placedon the table 2, the band 3 fed through the opening 7 of the guide member8 winds round the package 1 together with the table 2, and the upperband holding member 4 holds the tip 3 of the band 3 by pressing itagainst the table 2.

The working mechanism of the table 2, the upper band holding member 4and the lower band holding member 5 in the present device is as shown inFIGS. 7 through 9. To be precise, the drive shaft 9 pivoted on the frameof machine is provided with the cams l0, l1 and 12 fixed thereon. Thelevers 13, 14 and 15 to work by virtue of these cams are pivoted on thesupporting shaft 16, and the tips of these levers are respectivelyengaged with the pin provided respectively on the table 2, the upperband holding member 4 and the lower band holding member 5 by means oftheir forked projection. The arms 17, 18 and 19 branching out from theselevers are engaged with the frame of machine by means of the springs 2011 and 22, respectively. The table 2 and the upper band holding member 4are connected with each other by means of the pin 23 and also providedwith the spring 24 interposed therebetween.

The table 2 is constructed by fitting the projections 25 provided onboth sides thereof into the grooves provided on the frame of machine asshown in FIG. 12. The top of the lower band holding member 5 is providedwith the projection 5a (FIG. 14) so disposed as to be located by theside of the upper band holding member 4 with the ascent of the lowerband holding member 5. Parallel to these band holding members 4 and 5,there are provided the heat member 6 whose top is equipped with thepectinate heat blades 6a disposed parallel to the direction of the bandand the press member 28 disposed above the heat member 6 and having awidth practically the same as that of said heat member 6. The width ofthe table 2-is almost equal to the total of the width of the lower bandholding member 5 and the width of the press member 28, to wit, the heatmember 6. The reference 8 denotes the guide member which is providedwith the cutter 8a, and 26 and 27 each denotes a leaf spring providedfor impact absorption purposes. I

The working mechanism of the heat member 6 and the press member 28 inthe foregoing device is as shown in FIGS.'10 and 11. That is, thesemembers work by virtue of the cams 29 and 30 fixed on the drive shaft 9,the tips of the levers 31 and 32 pivoted on the supporting shaft 16 arerespectively engaged with the pin provided respectively on the pressmember 28 and the heat member 6 by means of their forked projection, andthe arms 33 and 34 branching out from these levers are engaged with theframe of machine by means of the springs 35 and 36, respectively. Thenumeral references 37 and 38 each denotes a leaf spring provided forimpact absorption purposes.

OPERATION In the state shown in FIG. 6, the levers 13 and 14 to work onthe table 2 and the upper band holding member 4 are engaged with thecams l0 and 11 as shown in FIGS. 7 and 8, respectively.

At this, when the drive shaft 9 rotates and the lever is engaged withthe cam 12 as shown in FIG. 9, the lever 15 turns clockwise centeringaround the supporting shaft 16 and the lower band holding member 5ascends to press the lower portion 3" of the band 3 by its top againstthe bottom surface of the upper band holding member 4 and also hold theband 3' by pressing it against the bottom surface of the table 2 by thetop of the projection 5a. a

At the same time, the lever 32 shown in FIG. 11 turns clockwisecentering around the supporting shaft 16 by virtue of the cam 30,whereby the heat member 6 is elevated and the band 3 is cut by theenergy of the cutter 6b provided on one shoulder of said heat member 6and the cutter 8a provided on the shoulder of the opening of the guidemember 8, and thereafter the heat blades 6a equipped on the top of theheat member 6 press the upper portion 3' and the lower portion 3" of theband against the bottom surface of the table 2 to melt and penetrate thethus overlapped portions 3' and 3" of said band (cf. FIG. 13).

Subsequently, the lever 32 turns counterclockwise centering around thesupporting shaft 16 by virtue of the cam 30, whereby the heat member 6descends and there is brought about the interstice Z between the heatmember 6 and the lower portion 3" of the band as shown in FIG. 14.

At this juncture, the lever 31 shown in FIG. 10 turns counterclockwisecentering around the supporting shaft 16 by virtue of the cam 29,whereby the press member 28 is made to advance into said interstice Z(cf. FIG. 14).

Thereafter, the lever 32 turns clockwise again by virtue of the cam 30and the heat member 6 ascends to thereby push up the bottom surface ofthe press member 28 by the heat blades 6a equipped on the top thereof(cf. FIG. 16), press the melted portions 3' and 3" of the band by thetop surface thereof against the bottom surface of the table 2, and weldthe band by said melted portions to complete the strapping work (cf.FIG. 15).

' The condition of the thus welded portions of the band is as shown inFIG. 17.

Although particular preferred embodiments of the present invention havebeen disclosed hereinabove for the purpose of illustration, it will beunderstood that variations or modifications thereofwhich lie within thescope of the invention as defined by the appended claims are fullycontemplated.

What is claimed is:

l. A device for cutting and welding a plastic band applicable to anautomatic strapping machine for the purpose of strapping the packagewith a thermoplastic band, which is characterized by the provision ofatable capable of longitudinal movement under the package, an upper bandholding member installed beneath one side of said table so as tocooperate therewith and be capable of vertical movement in relationthereto, a press member installed beneath the other side of said tableso as to be capable of longitudinal movement, a lower band holdingmember installed beneath said upper band holding member so as to becapable of vertical movement, a heat member installed beneath said pressmember so as to be capable of vertical movement, said heat member beingprovided with plural heat blades disposed parallel to the direction ofstrain .of said band, and means for cutting cutting said band.

2. A device for cutting and welding a plastic band as defined in claim1, wherein the width of said table is almost equal to the total of thewidth of said lower band holding member and the width of said heatmember.

3. An apparatus for welding the overlapping end portions of an elongatedthermoplastic strapping band, such as for securing said band insurrounding relationship to a package, comprising:

a movable table adapted to have a package positioned thereon;

a first band holding member positioned beneath said table and meansmounting said first holding member for vertical movement for permittingone of said end portions of said band to be clamped between said tableand said first holding member;

a second band holding member disposed below said first band holdingmember and means mounting said second holding member for verticalmovement toward said first holding member for permitting the other endportion of said band member to be clamped between said first and secondholding members;

heating means disposed below said table and means mounting same formovement toward and away from said table, said heating means including aheating head disposed for engaging and melting the overlapping endportions of said band, whereby movement of said heating means towardsaid table causes the overlapping end portions of said band means to bepositioned between said table and said heating head; and

a pressing member disposed below said table and means mounting saidpressing member for substantially horizontal movement between a firstposition wherein said pressing member is disposed between the heatinghead and the overlapping end portions of said band and a second positionwherein said pressing member is laterally spaced from said firstposition, whereby upward movement of said heating means when saidpressing member is in said first position causes said pressing member tocover said heating head so that said pressing member causes thepreviously heated overlapping end portions of said band to be pressedagainst the undersurface of said table.

4. An apparatus according to claim 3, further including means coactingwith said table for moving same horizontally for permitting said tableto be withdrawn from between said package and the overlapping portionsof said band;

said first band holding member comprising a lever pivotally mounted onsaid table and disposed for swinging movement within a substantiallyvertical plane, said lever being horizontally movable with said tableportion, said lever having a band engaging portion disposed thereonadjacent the free end thereof; and

spring means coacting between said lever and said table for normallymaintaining said band engaging portion spaced from the undersurface ofsaid table.

5. An apparatus according to claim 4, wherein the movement of saidtable, said second band holding member, said heating means and saidpressing member are individually controlled by means of a plurality ofswingable driving levers, and a plurality of rotatable drive camsrespectively disposed in driving engagement with said driving levers forcontrolling the movement thereof.

6. An apparatus according to claim 4, wherein said heating head includesa plurality of elongated and substantially parallel blades which atleast partially penetrate and melt the overlapping end portions of saidband, and wherein said pressing member includes a caplike portion whichcovers said blades when said pressing member is in said first position.

7. An apparatus according to claim 3, wherein said heating head includesa plurality of elongated and substantially parallel blades which areadapted to at least partially penetrate and melt the overlapping endportion of said band, said blades extending in a direction substantiallyparallel to the direction of strain of said band.

1. A device for cutting and welding a plastic band applicable to anautomatic strapping machine for the purpose of strapping the packagewith a thermoplastic band, which is characterized by the provision of atable capable of longitudinal movement under the package, an upper bandholding member installed beneath one side of said table so as tocooperate therewith and be capable of vertical movement in relationthereto, a press member installed beneath the other side of said tableso as to be capable of longitudinal movement, a lower band holdingmember installed beneath said upper band holding member so as to becapable of vertical movement, a heat member installed beneath said pressmember so as to be capable of vertical movement, said heat member beingprovided with plural heat blades disposed parallel to the direction ofstrain of said band, and means for cutting cutting said band.
 2. Adevice for cutting and welding a plastic band as defined in claim 1,wherein the width of said table is almost equal to the total of thewidth of said lower band holding member and the width of said heatmember.
 3. An apparatus for welding the overlapping end portions of anelongated thermoplastic strapping band, such as for securing said bandin surrounding relationship to a package, comprising: a movable tableadapted to have a package positioned thereon; a first band holdingmember positioned beneath said table and means mounting said firstholding member for vertical movement for permitting one of said endportions of said band to be clamped between said table and said firstholding member; a second band holding member disposed below said firstband holding member and means mounting said second holding member forvertical movement toward said first holding member for permitting theother end portion of said band member to be clamped between said firstand second holding members; heating means disposed below said table andmeans mounting same for movement toward and away from said table, saidheating means including a heating head disposed for engaging and meltingthe overlapping end portions of said band, whereby movement of saidheating means toward said table causes the overlapping end portions ofsaid band means to be positioned between said table and said heatinghead; and a pressing member disposed below said table and means mountingsaid pressing member for substantially horizontal movement between afirst position wherein said pressing member is disposed between theheating head and the overlapping end portions of said band and a secondposition wherein said pressing member is laterally spaced from saidfirst position, whereby upward movement of said heating means when saidpressing member is in said first position causes said pressing member tocover said heating head so that said pressing member causes thepreviously heated overlapping end portions of said band to be pressedagainst the undersurface of said table.
 4. An apparatus according toclaim 3, further including means coacting with said table for movingsame horizontally for permitting said table to be withdrawn from betweensaid package and the overlapping portions of said band; said first bandholding member comprising a lever pivotally mounted on said table anddisposed for swinging movement within a substantially vertical plane,said lever being horizontally movable with said table portion, saidlever having a band engaging portion disposed thereon adjacent the freeend thereof; and spring means coacting between said lever and said tablefor normally maintaining said band engaging portion spaced from theundersurface of said table.
 5. An apparatus according to claim 4,wherein the movement of said table, said second band holding member,said heating means and said pressing member are individually controlledby means of a plurality of swingable driving levers, and a plurality ofrotatable drive cams respectively disposed in driving engagement withsaid driving levers for controlling the movement thereof.
 6. Anapparatus according to claim 4, wherein said heating head includes aplurality of elongAted and substantially parallel blades which at leastpartially penetrate and melt the overlapping end portions of said band,and wherein said pressing member includes a caplike portion which coverssaid blades when said pressing member is in said first position.
 7. Anapparatus according to claim 3, wherein said heating head includes aplurality of elongated and substantially parallel blades which areadapted to at least partially penetrate and melt the overlapping endportion of said band, said blades extending in a direction substantiallyparallel to the direction of strain of said band.